Field of Invention
The present invention relates to a direct current to direct current (DC/DC) power supply apparatus. More particularly, the present invention relates to a DC/DC power supply apparatus.
Description of Related Art
Some of the direct current to direct current (DC/DC) converter modules are suitable for use in the power supply system of apparatus for telecommunication and data communication; such DC/DC converter modules receive the DC voltage from the system and then convert the same into a DC voltage with an appropriate level. Products of this type are often directly mounted on a system board, and are referred to as board mounted power (BMP) modules. As the primary power supply converting unit, such product usually employs a printed circuit board as the transformer winding (also known as PCB winding), in which the power circuit and the control circuit are integrated in a printed circuit board, and hence it possesses higher power density and good heat dissipation efficiency; however, due to the limitation of the height of the system, in most cases, the power produced by a single modules cannot be too great; generally, the power is often dozens to several hundreds of watts.
With the continuous advancement of the apparatus for telecommunication and data communication, the demand for the power of the electricity also increases from several hundreds of watts to several thousands of watts. Conventionally, when a power supply converter with a great power output is desired, a DC/DC converter with a greater power output is used, in which the output levels of the transformer and power device are amplified in proportion to the power ratio; for example, for a system of 1000 watts, a DC/DC converter with a power output of 1000 watts is used. For an apparatus capable of outputting power of several hundreds or even thousands of watts, the transformer are often manufactured using the conventional separate structure; however, such transformer would result in a greater leakage inductance so that the converting efficiency of the transformer is lower than the converting efficiency of the modularized power supply; meanwhile, since a single transformer is used, the size of this transformer is greater, which may affect the design of the wind channel of the power supply system; in particular, in the design where the demand for power density is higher, it is difficult to take into consideration the requirement for heat dissipation, and thus, the solution to this problem is often resolved by increasing the wind flow of the system.
Moreover, since the design of the transformer and power circuit often depends on the power level of the convertor, when the designers face multiple product development projects, they cannot utilize the existing resources, thereby resulting in a great deal of repetitive labor investment and a longer design and development period.
FIG. 1 is an alternative to the above-discussed conventional designs, in which several DC/DC board mounted power modules with smaller power are connected in parallel to fulfill the need for the power supply convertor with a greater power output. For example, for a system with 1000 watts of power, 10 modules with 100 watts of power can be connected in parallel.
Using the DC/DC power supply converter as the board mounted power is advantageous in that the board mounted power can shorten the distance between the product and the load so as to greatly reduce the loss of the connecting line, and hence guarantees the EMI and output index. Further, the product can be ordered depending on the actual need of the load. Moreover, the convertor is an isolation-type product, which can be easily configured in digital or analogous ways. Since the board mounted power module has the advantage of high power density, this solution maintains the advantages of high power density and good heat dissipation efficiency of the DC/DC converter module, thereby providing a reliable power supply. However, in FIG. 1, each board mounted power module has to comprise a power circuit and a corresponding control circuit, so that the control circuit is used to control the power switch of the power circuit; this would result in an increase of the amount of the control circuit in the whole system, thereby causing a drastic increase of the cost of the device. Moreover, the system board may further require a current equalizing circuit or a monitoring circuit to ensure the balance among the plurality of board mounted power modules. Additionally, since the heat dissipation conditions across the system may not be the same, the temperature elevations of various board mounted power modules may be different, and hence the efficiency of each module cannot be maximized, and hence the number of parallel-connected modules is somewhat limited.
In view of the foregoing, there exists a need in the related art for a power supply product with high power density and high efficiency while possessing specific flexibility and compatibility. From the perspective of the design period of the power supply, the skilled artisan also faces the challenge of developing a simpler, more flexible and environmentally-friendly process for manufacturing the power supply product.